crcxm.h

一个在Visual c++下可对串口和MODEM进行操作,并能用ZOMDEM协议进行收发文件的程序.

/*********************************************************************/
/*                                                                   */
/*  crcxm.h - calculate crc's for use by Xmodem.                     */
/*                                                                   */
/*                                                                   */
/*  The following things are defined:                                */
/*                                                                   */
/*  crcxm - a data type that contains the information required by    */
/*          these routines.                                          */
/*                                                                   */
/*  crcxmInit - initialize the crcxm structure.  This routine        */
/*          should be called before using any of the other routines  */
/*                                                                   */
/*  crcxmUpdate - expects a parameter of an integer, which contains  */
/*          a value from 0 to 255.  No bounds checking is done, so   */
/*          you must ensure that you pass the correct value.  ie, if */
/*          you are using a signed char field to store a character   */
/*          make sure you typecast it to unsigned int!               */
/*                                                                   */
/*  crcxmValue - returns an unsigned int containing the crc value    */
/*                                                                   */
/*  crcxmHighbyte - returns the high-byte of the crc                 */
/*                                                                   */
/*  crcxmLowbyte - returns the low-byte of the crc                   */
/*                                                                   */
/*                                                                   */
/*  Example:                                                         */
/*                                                                   */
/*  #include "crcxm.h"                                               */
/*                                                                   */
/*  CRCXM crc;                                                       */
/*                                                                   */
/*  crcxmInit(&crc);                                                 */
/*  crcxmUpdate(&crc, 'C');                                          */
/*  crcxmUpdate(&crc, 'R');                                          */
/*  crcxmUpdate(&crc, 'C');                                          */
/*  printf("crc is %x\n", crcxmValue(&crc));                         */
/*  printf("high byte is %x\n", crcxmHighbyte(&crc));                */
/*  printf("low byte is %x\n", crcxmLowbyte(&crc));                  */
/*                                                                   */
/*  Would print (assuming an ASCII machine):                         */
/*                                                                   */
/*  crc is 5487                                                      */
/*  high byte is 54                                                  */
/*  low byte is 87                                                   */
/*                                                                   */
/*********************************************************************/

#ifndef CRCXM_INCLUDED
#define CRCXM_INCLUDED

static unsigned int crcxm_tab[256] = {

 0x0000U, 0x1021U, 0x2042U, 0x3063U, 0x4084U, 0x50A5U, 0x60C6U, 0x70E7U,
 0x8108U, 0x9129U, 0xA14AU, 0xB16BU, 0xC18CU, 0xD1ADU, 0xE1CEU, 0xF1EFU,
 0x1231U, 0x0210U, 0x3273U, 0x2252U, 0x52B5U, 0x4294U, 0x72F7U, 0x62D6U,
 0x9339U, 0x8318U, 0xB37BU, 0xA35AU, 0xD3BDU, 0xC39CU, 0xF3FFU, 0xE3DEU,
 0x2462U, 0x3443U, 0x0420U, 0x1401U, 0x64E6U, 0x74C7U, 0x44A4U, 0x5485U,
 0xA56AU, 0xB54BU, 0x8528U, 0x9509U, 0xE5EEU, 0xF5CFU, 0xC5ACU, 0xD58DU,
 0x3653U, 0x2672U, 0x1611U, 0x0630U, 0x76D7U, 0x66F6U, 0x5695U, 0x46B4U,
 0xB75BU, 0xA77AU, 0x9719U, 0x8738U, 0xF7DFU, 0xE7FEU, 0xD79DU, 0xC7BCU,
 0x48C4U, 0x58E5U, 0x6886U, 0x78A7U, 0x0840U, 0x1861U, 0x2802U, 0x3823U,
 0xC9CCU, 0xD9EDU, 0xE98EU, 0xF9AFU, 0x8948U, 0x9969U, 0xA90AU, 0xB92BU,
 0x5AF5U, 0x4AD4U, 0x7AB7U, 0x6A96U, 0x1A71U, 0x0A50U, 0x3A33U, 0x2A12U,
 0xDBFDU, 0xCBDCU, 0xFBBFU, 0xEB9EU, 0x9B79U, 0x8B58U, 0xBB3BU, 0xAB1AU,
 0x6CA6U, 0x7C87U, 0x4CE4U, 0x5CC5U, 0x2C22U, 0x3C03U, 0x0C60U, 0x1C41U,
 0xEDAEU, 0xFD8FU, 0xCDECU, 0xDDCDU, 0xAD2AU, 0xBD0BU, 0x8D68U, 0x9D49U,
 0x7E97U, 0x6EB6U, 0x5ED5U, 0x4EF4U, 0x3E13U, 0x2E32U, 0x1E51U, 0x0E70U,
 0xFF9FU, 0xEFBEU, 0xDFDDU, 0xCFFCU, 0xBF1BU, 0xAF3AU, 0x9F59U, 0x8F78U,
 0x9188U, 0x81A9U, 0xB1CAU, 0xA1EBU, 0xD10CU, 0xC12DU, 0xF14EU, 0xE16FU,
 0x1080U, 0x00A1U, 0x30C2U, 0x20E3U, 0x5004U, 0x4025U, 0x7046U, 0x6067U,
 0x83B9U, 0x9398U, 0xA3FBU, 0xB3DAU, 0xC33DU, 0xD31CU, 0xE37FU, 0xF35EU,
 0x02B1U, 0x1290U, 0x22F3U, 0x32D2U, 0x4235U, 0x5214U, 0x6277U, 0x7256U,
 0xB5EAU, 0xA5CBU, 0x95A8U, 0x8589U, 0xF56EU, 0xE54FU, 0xD52CU, 0xC50DU,
 0x34E2U, 0x24C3U, 0x14A0U, 0x0481U, 0x7466U, 0x6447U, 0x5424U, 0x4405U,
 0xA7DBU, 0xB7FAU, 0x8799U, 0x97B8U, 0xE75FU, 0xF77EU, 0xC71DU, 0xD73CU,
 0x26D3U, 0x36F2U, 0x0691U, 0x16B0U, 0x6657U, 0x7676U, 0x4615U, 0x5634U,
 0xD94CU, 0xC96DU, 0xF90EU, 0xE92FU, 0x99C8U, 0x89E9U, 0xB98AU, 0xA9ABU,
 0x5844U, 0x4865U, 0x7806U, 0x6827U, 0x18C0U, 0x08E1U, 0x3882U, 0x28A3U,
 0xCB7DU, 0xDB5CU, 0xEB3FU, 0xFB1EU, 0x8BF9U, 0x9BD8U, 0xABBBU, 0xBB9AU,
 0x4A75U, 0x5A54U, 0x6A37U, 0x7A16U, 0x0AF1U, 0x1AD0U, 0x2AB3U, 0x3A92U,
 0xFD2EU, 0xED0FU, 0xDD6CU, 0xCD4DU, 0xBDAAU, 0xAD8BU, 0x9DE8U, 0x8DC9U,
 0x7C26U, 0x6C07U, 0x5C64U, 0x4C45U, 0x3CA2U, 0x2C83U, 0x1CE0U, 0x0CC1U,
 0xEF1FU, 0xFF3EU, 0xCF5DU, 0xDF7CU, 0xAF9BU, 0xBFBAU, 0x8FD9U, 0x9FF8U,
 0x6E17U, 0x7E36U, 0x4E55U, 0x5E74U, 0x2E93U, 0x3EB2U, 0x0ED1U, 0x1EF0U };

#define crcxmInit(crc) ((*(crc)) = 0U)

#define crcxmUpdate(crc, ch) \
    ((*(crc)) = ((((*(crc)) & 0xffU) << 8) ^ \
    crcxm_tab[(unsigned char)((ch) ^ ((*(crc)) >> 8))]))

#define crcxmValue(crc) (*(crc))

typedef unsigned int CRCXM;

#define crcxmLowbyte(crc) ((*(crc)) & 0xffU)

#define crcxmHighbyte(crc) (((*(crc)) >> 8) & 0xffU)

#endif